Method for producing lamella packets for adjustable steering columns
The invention relates to a method for producing lamella packets (e.g. 70) such as those used for adjustable steering columns in automobiles. According to the invention, at least one of the lamellae (e.g. 71) is provided with a collar (71.1) and is joined to another lamella (e.g. 72) so that the collar (71.1) of the first lamella (71) is supported against the other lamella (72) whereby defining the width (B) of a space between the lamellae (71, 72). Both lamellae (71, 72) are welded at at least one location of the collar (71.1). The welding is preferably carried out by resistance welding. In order to obtain defined ratios, the edge of the lamella collar (71.1) is preferably provided with projecting points (Z). The method is, among other things, advantageous in that the same material quality can be used for all lamellae (1–74).
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The present invention relates to a method for producing lamella packets, as are used for adjustable steering columns in cars, at least one of the lamellae being provided with a collar and being joined to another lamella in such a manner that the collar of the one lamella is supported against the other lamella and thereby determines the width of a gap between the lamellae.
PRIOR ARTWO 01/28710 discloses a method of this type, this document also discussing the design of the lamella packets as longitudinal and height lamellae and explaining the function thereof.
In the previously known method, the lamella packets are composed in each case of at least one soft lamella made of a softer sheet-metal material and of at least one hard lamella made of a harder sheet-metal material, a rivet being produced from the softer lamella in order to connect the lamellae. This connection technique has the advantage of not requiring and having to supply any additional components in order to connect the lamellae. However, the method requires the use of two presses because of the different materials. Only the soft lamellae are produced in the one press and the hard lamellae are produced in the other press. The soft lamellae are transported from the one press into the other press where the lamellae are also stacked, and the rivet is produced from the soft disk. The two different materials are necessary because the rivet cannot be formed from the harder material and, on the other hand, the softer material does not withstand the loads to which the lamella packets are subjected. In the known method, the number of lamellae in the packet is also determined by the maximum possible rivet height.
SUMMARY OF THE INVENTIONThe invention has set itself the object of specifying a method of the type mentioned at the beginning which is less costly in terms of material and manufacturing technology and in which the number of lamellae in the packet can also largely be freely selected. This object is achieved according to the invention by a method as characterized in patent claim 1. According to this, the lamellae are welded to each other at at least one location on the collar.
The advantages of the method according to the invention are:
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- only one tool, for example in the form of a follow-on composite tool, is required per lamella packet (longitudinal and vertical lamellae);
- only one press is required;
- the number of lamellae per packet can be selected relatively freely and is not restricted by a limit provided by the ability of a rivet to be pulled out;
- the same quality of material can be used for all of the lamellae;
- only simple lamella geometries have to be produced, in particular no lamellae with high rivet collars, this having a simplifying effect on the design of the tools;
- the welding of the shafts can take place in a separate working step outside the press; this also has a simplifying effect on the design of the tools and, in addition, permits higher speeds of production.
According to a first preferred embodiment, the welding is implemented by resistance welding. In this connection, it is advantageous if the collar is produced in some sections at a height corresponding to the desired width of the gap between the lamellae, and is provided with at least one tooth protruding above the said height. The tooth is then melted back to the said height during the resistance welding. In order to receive the volume of the tooth or projecting point displaced in this process, depressions can be provided on the collar adjacent to the tooth. A plurality of teeth, in particular three teeth, are advantageously provided along the edge of the collar.
According to a further preferred embodiment, the same material is used for all of the lamellae.
The invention will be explained in greater detail below with reference to exemplary embodiments in conjunction with the drawings, in which:
According to the invention, the lamellae are preferably welded by resistance welding. During the resistance welding, the metal parts which are to be welded to one another are brought into contact with one another and are then connected to the poles of a source of current. The current then flowing over the contact surface of the metal parts produces heat in the environment of this surface, the heat causing the metal on both sides of the contact surface to liquefy and fuse together. It is favorable for the method if the geometry of the parts is selected in such a manner that the cross section for the flow of current in the region of its contact surface is minimal. The ohmic resistance is then conversely at its maximum there, and most of the heat loss occurs locally there.
Correspondingly, as
Owing to the teeth, the mutual distance between the lamellae and the width B of their gaps before welding is somewhat larger than the said height H, as can also be seen in
So that the excess welding material arising during the squeezing away of the teeth in the described manner can flow to a defined location, respective depressions can also be provided on both sides of the teeth in the edges of the collars, as is also illustrated in
For its implementation in terms of machinery for producing the lamellae, the method according to the invention requires just two tools (one for the vertical lamellae and one for the longitudinal lamellae), in particular follow-on composite tools, with which the lamellae are produced from one metal strip in each case in a number of steps. The two tools can be arranged in the same press. The lamellae are preferably also stacked one above another in each case in the tools. In contrast, the lamellae are preferably welded in a separate welding station arranged downstream of the press.
LIST OF REFERENCE NUMBERS
- 10 The axis of the steering column
- 20 Guide box
- 30, 40 Bearings for the steering column in the guide box
- 50 Retaining shackle fixed on the chassis
- 60 Vertical lamella racket, height lamella packet
- 61–64 Lamellae
- 65, 66 Fastening eyelets
- 67 Guide slot
- 68 Trough-shaped formation
- 70 Longitudinal lamella packet
- 71–74 Lamellae
- 71.1–73.1 Collars
- 75, 76 Fastening eyelets
- 77 Guide slot
- 78 Frictional surfaces 78
- 80 Clamping bolts 80
- 81 Head part of the clamping bolt 80
- 90 Locking lever for the clamping bolt 80
- H Height of the collars
- B Width of the lamella gaps
- Z Teeth, projecting points
- V Depressions on both sides of the teeth
Claims
1. A method for producing lamella packets (e.g. 70), as are used for adjustable steering columns in cars, at least one of the lamellae (e.g. 71) being provided with a collar (71.1) and being joined to another lamella (e.g. 72) in such a manner that the collar (71.1) of the one lamella (71) is supported against the other lamella (72) and thereby determines the width (B) of a gap between the lamellae (71, 72), characterized in that the two lamellae (71, 72) are welded to each other at at least one location (e.g. S) on the collar (71.1).
2. The method as claimed in claim 1, characterized in that the welding is implemented by resistance welding.
3. A method for producing lamella packets (e.g. 70), as are used for adjustable steering columns in cars, at least one of the lamellae (e.g. 71) being provided with a collar (71.1) and being joined to another lamella (e.g. 72) in such a manner that the collar (71.1) of the one lamella (71) is supported against the other lamella (72) and thereby determines the width (B) of a gap between the lamellae (71, 72), characterized in that the two lamellae (71, 72) are resistance welded to each other at at least one location (e.g. S) on the collar (71.1),
- the collar (71.1) being produced in some sections at a height (H) corresponding to the desired width (B) of the gap between the lamellae, and is provided with at least one tooth (Z) protruding above this height (H).
4. The method as claimed in claim 3, characterized in that the at least one tooth (Z) is melted back to the said height (H) during the resistance welding.
5. The method as claimed in claim 4, characterized in that respective depressions (V) for receiving the volume of the at least one tooth (Z) displaced during the resistance welding are provided on the collar (71.1) adjacent to the at least one tooth (Z).
6. The method as claimed in one of claim 1, characterized in that the same material is used for all of the lamellae (61–64, 71–74).
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- Designing Shapes for Projection Welding, Tech Briefs, Machine Design, 60 (1988) Jun. 9, No. 13. Cleveland, Ohio, U.S.
Type: Grant
Filed: Jun 17, 2002
Date of Patent: Mar 28, 2006
Patent Publication Number: 20040182829
Assignee: Adval Tech Holding AG (Niederwangen)
Inventor: Hans Jöhr (Kehrsatz)
Primary Examiner: Kevin Kerns
Assistant Examiner: Michael Aboagye
Attorney: Tarolli, Sundheim, Covell & Tummino L.L.P.
Application Number: 10/481,491
International Classification: B23K 11/00 (20060101); B23K 11/14 (20060101);